[project @ 2003-04-11 13:04:37 by simonmar]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcRules.lhs

diff --git a/ghc/compiler/typecheck/TcRules.lhs b/ghc/compiler/typecheck/TcRules.lhs
index 0688922..492e9ab 100644 (file)
--- a/ghc/compiler/typecheck/TcRules.lhs
+++ b/ghc/compiler/typecheck/TcRules.lhs
@@ -8,21 +8,20 @@ module TcRules ( tcRules ) where
 
 #include "HsVersions.h"
 
-import HsSyn           ( RuleDecl(..), RuleBndr(..), HsExpr(..), collectRuleBndrSigTys )
+import HsSyn           ( RuleDecl(..), RuleBndr(..), collectRuleBndrSigTys )
 import CoreSyn         ( CoreRule(..) )
 import RnHsSyn         ( RenamedRuleDecl )
-import TcHsSyn         ( TypecheckedRuleDecl, TcExpr, mkHsLet )
+import TcHsSyn         ( TypecheckedRuleDecl, mkHsLet )
 import TcRnMonad
 import TcSimplify      ( tcSimplifyToDicts, tcSimplifyInferCheck )
 import TcMType         ( newTyVarTy )
-import TcType          ( TcTyVarSet, tyVarsOfTypes, tyVarsOfType, openTypeKind )
-import TcIfaceSig      ( tcCoreExpr, tcCoreLamBndrs, tcVar )
+import TcType          ( tyVarsOfTypes, openTypeKind )
+import TcIfaceSig      ( tcCoreExpr, tcCoreLamBndrs )
 import TcMonoType      ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
 import TcExpr          ( tcMonoExpr )
-import TcEnv           ( tcExtendLocalValEnv )
+import TcEnv           ( tcExtendLocalValEnv, tcLookupGlobalId, tcLookupId )
 import Inst            ( instToId )
 import Id              ( idType, mkLocalId )
-import VarSet
 import Outputable
 \end{code}
 
@@ -34,14 +33,21 @@ tcRule :: RenamedRuleDecl -> TcM TypecheckedRuleDecl
 tcRule (IfaceRule name act vars fun args rhs src_loc)
   = addSrcLoc src_loc          $
     addErrCtxt (ruleCtxt name) $
-    tcVar fun                          `thenM` \ fun' ->
+    tcLookupGlobalId fun               `thenM` \ fun' ->
     tcCoreLamBndrs vars                        $ \ vars' ->
     mappM tcCoreExpr args              `thenM` \ args' ->
     tcCoreExpr rhs                     `thenM` \ rhs' ->
     returnM (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
 
-tcRule (IfaceRuleOut fun rule) -- Built-in rules come this way
-  = tcVar fun                          `thenM` \ fun' ->
+tcRule (IfaceRuleOut fun rule) -- Built-in rules, and only built-in rules, 
+                               -- come this way.  Usually IfaceRuleOut is only
+                               -- used for the *output* of the type checker
+  = tcLookupId fun             `thenM` \ fun' ->
+       -- NB: tcLookupId, not tcLookupGlobalId
+       -- Reason: when compiling GHC.Base, where eqString is defined,
+       --         we'll get the builtin rule for eqString, but eqString
+       --         will be in the *local* type environment.
+       -- Seems like a bit of a hack
     returnM (IfaceRuleOut fun' rule)   
 
 tcRule (HsRule name act vars lhs rhs src_loc)